The present invention relates to a method for laying elongated winding material, such as for example wire, insulated or non-insulated strands, glass fibers, and the like, as well as a device for executing the method.
In known winding methods, a strand-type material is for example attached to a rotating spool and is thus wound onto the core of the spool. In order to achieve a layered winding, i.e. to lay the wire windings next one another on the spool, a deflection roller that guides the winding material to the spool moves essentially parallel to the axial direction of the rotating spool. It is also known to situate the spool in stationary fashion and to cause a flyer that also moves axially to move around the spool, said flyer laying the winding material around the spool in layers.
In order to obtain a particular type of winding (layer on layer), it is also known to cause the axially displaceable laying unit on which the deflecting roller is situated to trail the normal pitch direction by a certain amount. In this way, between the material being wound on and the winding already in place there arises a lateral pressure that lays the winding material in the desired manner up to the last winding of the relevant layer.
If the laying unit does not reverse its direction of motion at the correct time, the winding material reaches the flange of the spool. It climbs onto the last winding of the completely wound layer and, if the change of direction still does not take place, forms what is called a “hill” in the winding directly on the flange.
Here, when the change of direction of the laying unit takes place too late, there results an axial pressure on the spool flange, which deforms elastically as a result, in particular in the case of plastic spools. On the one hand, this has a disadvantageous effect on the durability of the plastic spools, and on the other hand the elastic reset forces of the flange cause problems in the later unwinding of the elongated winding material from the spool.
Immediately after the change of direction of the laying unit in the winding process, the counter-pressure of a previous winding is not present. For this reason, the winding material at this location has the tendency to wind on with larger spacings at the beginning, i.e. with a larger pitch, dependent on the size of the feeding angle. In this way, at the beginning of each winding layer there arise intermediate spaces, called “valleys,” into which the windings of the layer situated thereabove are wound, which can cause difficulties in the later unwinding of the winding material.
However, if the change of direction of the laying unit takes place too late, as mentioned above a plurality of windings overlap at the relevant spool flange. Such piles of winding layers are called hills. As a result of these phenomena, non-uniform layers are formed, especially in the edge areas of the winding.
The formation of hills and valleys is also caused by an improper setting of the laying width of the winding material, or, as mentioned, by a deformation of the spool flange.
In addition to the non-uniform and therefore unsatisfactory use of the winding space caused by the formation of hills and valleys, the winding material is also excessively stressed, and can thus be damaged.
Therefore, for the most optimal use of the winding space, as well as in order to avoid an elastic deformation of spool flanges, it should be sought to avoid the formation of hills and valleys during the layered laying of the winding material.
For the purpose of speed synchronization, control devices, known as “dancers,” are known that influence either the running speed of the spool or the running speed of the flyer circulating around the spool. In order to detect hills and valleys, for example the speed of the winding material is determined via the dancer signal or by an analog tachometer. These methods supply relatively imprecise signals on the basis of which no conclusion can be drawn concerning the amplitudes of the hills and valleys.
From DE 196 45 992 A1, a control device is known that has a rotational speed sensor for determining the rotational speed of a flyer or of a winder, and has a control unit for picking up signals of the rotational speed sensor, and has a laying unit for applying the elongated winding material onto the spool. For the controlling of the laying unit, the control unit can control the laying unit corresponding to a determined laying speed target value, and carry out a laying width adjustment. An automatic laying width adjustment can also be realized. Here, for example the tolerances of the spool are taken into account, or also the change in spool dimensions that can result from an elastic deformation of the flange during winding. In addition, the control unit can carry out an automatic reverse point correction. At slow rotational speeds, the laying width deviation is determined by modifying the rotational speed in relation to a reference rotational speed that is measured at the center of the spool. At higher rotational speeds, a dancer signal is used that controls the winder.
For the digital detection of hills and valleys, other known systems use as a parameter the wire feed length, relative to a particular number of spool rotations. Here, an average diameter on the spool is determined, and this is compared with the diameters at the reverse points.
A disadvantage of both these systems is the indirect detection of the winding quality on the basis of parameters such as rotational speed, wire feed length, or laying speed. A laying width adjustment cannot be carried out until deviations of these parameters occur or the spool flange is already deformed, i.e., until a “significantly” non-uniform winding pattern has already occurred.
In DE 200 084 05 U1, it is proposed that a laser distance sensor be attached in such a way that its laser beam forms a line that is aligned with the wire that is to be spooled. This laser distance sensor acquires the distance to a winding material wound onto a spool body, and outputs the value to an SPS control unit. This control unit compares the value with stored data, calculates and evaluates modifications, and sends control signals to a laying unit, which as a result changes its speed so that a uniform winding on the spool results. Here, the laser distance sensor also recognizes the flange of the spool body. This large distance change is evaluated in the control unit as a turning signal, and results in an automatic reversal of the direction of movement of the laying unit.
A disadvantage of this system is that the laser distance sensor acquires only the distance from the deflecting roller to the winding material. The diameter of the winding is not determined, and is not taken into account. It is true that in this way a signal can be derived for accelerating or retarding the shifting unit, but an exact calculation of the speed of the laying device required for the compensation of the non-uniform surface is not possible in the manner described.
Due to the situation of the laser distance sensor, which is aligned with the winding material that is to be spooled, the spool flange is not recognized until the laying unit with the winding material is positioned at the height of the spool flange. The optimum time for reversing the direction of travel of the laying unit is then already past. This results in an elastic deformation of the spool flange and the formation of a hill leaning on the flange.
The use of the known method for improving the winding pattern in the laying of winding material is also made more difficult if the supply of energy and the exchange of signals, such as in the case of stranding machines, is possible only via rotating components.
The present invention is based on the object of making available a method for laying elongated winding material that produces the best possible winding pattern on arbitrary spools, without hills and valleys. In addition, the method should be as user-friendly as possible, and should be capable of being used with all spool systems. In addition, a device is to be indicated for the execution of this method that enables the supply of energy and the exchange of signals via rotating components.